Expand 64-bit shifts if target ABI is O32.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@156457 91177308-0d34-0410-b5e6-96231b3b80d8

3 files changed, 112 insertions, 3 deletions

diff --git a/lib/Target/Mips/MipsISelLowering.cpp b/lib/Target/Mips/MipsISelLowering.cpp
index 337a5e3..d5cc747 100644
--- a/lib/Target/Mips/MipsISelLowering.cpp
+++ b/lib/Target/Mips/MipsISelLowering.cpp
@@ -164,6 +164,12 @@ MipsTargetLowering(MipsTargetMachine &TM)
     setOperationAction(ISD::DYNAMIC_STACKALLOC, MVT::i64,   Custom);
   }
 
+  if (!HasMips64) {
+    setOperationAction(ISD::SHL_PARTS,          MVT::i32,   Custom);
+    setOperationAction(ISD::SRA_PARTS,          MVT::i32,   Custom);
+    setOperationAction(ISD::SRL_PARTS,          MVT::i32,   Custom);
+  }
+
   setOperationAction(ISD::SDIV, MVT::i32, Expand);
   setOperationAction(ISD::SREM, MVT::i32, Expand);
   setOperationAction(ISD::UDIV, MVT::i32, Expand);
@@ -199,9 +205,6 @@ MipsTargetLowering(MipsTargetMachine &TM)
   if (!Subtarget->hasMips64r2())
     setOperationAction(ISD::ROTR, MVT::i64,   Expand);
 
-  setOperationAction(ISD::SHL_PARTS,         MVT::i32,   Expand);
-  setOperationAction(ISD::SRA_PARTS,         MVT::i32,   Expand);
-  setOperationAction(ISD::SRL_PARTS,         MVT::i32,   Expand);
   setOperationAction(ISD::FSIN,              MVT::f32,   Expand);
   setOperationAction(ISD::FSIN,              MVT::f64,   Expand);
   setOperationAction(ISD::FCOS,              MVT::f32,   Expand);
@@ -750,6 +753,9 @@ LowerOperation(SDValue Op, SelectionDAG &DAG) const
     case ISD::FRAMEADDR:          return LowerFRAMEADDR(Op, DAG);
     case ISD::MEMBARRIER:         return LowerMEMBARRIER(Op, DAG);
     case ISD::ATOMIC_FENCE:       return LowerATOMIC_FENCE(Op, DAG);
+    case ISD::SHL_PARTS:          return LowerShiftLeftParts(Op, DAG);
+    case ISD::SRA_PARTS:          return LowerShiftRightParts(Op, DAG, true);
+    case ISD::SRL_PARTS:          return LowerShiftRightParts(Op, DAG, false);
   }
   return SDValue();
 }
@@ -1964,6 +1970,78 @@ SDValue MipsTargetLowering::LowerATOMIC_FENCE(SDValue Op,
                      DAG.getConstant(SType, MVT::i32));
 }
 
+SDValue MipsTargetLowering::LowerShiftLeftParts(SDValue Op,
+                                                SelectionDAG& DAG) const {
+  DebugLoc DL = Op.getDebugLoc();
+  SDValue Lo = Op.getOperand(0), Hi = Op.getOperand(1);
+  SDValue Shamt = Op.getOperand(2);
+
+  // if shamt < 32:
+  //  lo = (shl lo, shamt)
+  //  hi = (or (shl hi, shamt) (srl (srl lo, 1), ~shamt))
+  // else:
+  //  lo = 0
+  //  hi = (shl lo, shamt[4:0])
+  SDValue Not = DAG.getNode(ISD::XOR, DL, MVT::i32, Shamt,
+                            DAG.getConstant(-1, MVT::i32));
+  SDValue ShiftRight1Lo = DAG.getNode(ISD::SRL, DL, MVT::i32, Lo,
+                                      DAG.getConstant(1, MVT::i32));
+  SDValue ShiftRightLo = DAG.getNode(ISD::SRL, DL, MVT::i32, ShiftRight1Lo,
+                                     Not);
+  SDValue ShiftLeftHi = DAG.getNode(ISD::SHL, DL, MVT::i32, Hi, Shamt);
+  SDValue Or = DAG.getNode(ISD::OR, DL, MVT::i32, ShiftLeftHi, ShiftRightLo);
+  SDValue ShiftLeftLo = DAG.getNode(ISD::SHL, DL, MVT::i32, Lo, Shamt);
+  SDValue Cond = DAG.getNode(ISD::AND, DL, MVT::i32, Shamt,
+                             DAG.getConstant(0x20, MVT::i32));
+  Lo = DAG.getNode(ISD::SELECT, DL, MVT::i32, Cond, DAG.getConstant(0, MVT::i32),
+                   ShiftLeftLo);
+  Hi = DAG.getNode(ISD::SELECT, DL, MVT::i32, Cond, ShiftLeftLo, Or);
+
+  SDValue Ops[2] = {Lo, Hi};
+  return DAG.getMergeValues(Ops, 2, DL);
+}
+
+SDValue MipsTargetLowering::LowerShiftRightParts(SDValue Op, SelectionDAG& DAG,
+                                                 bool IsSRA) const {
+  DebugLoc DL = Op.getDebugLoc();
+  SDValue Lo = Op.getOperand(0), Hi = Op.getOperand(1);
+  SDValue Shamt = Op.getOperand(2);
+
+  // if shamt < 32:
+  //  lo = (or (shl (shl hi, 1), ~shamt) (srl lo, shamt))
+  //  if isSRA:
+  //    hi = (sra hi, shamt)
+  //  else:
+  //    hi = (srl hi, shamt)
+  // else:
+  //  if isSRA:
+  //   lo = (sra hi, shamt[4:0])
+  //   hi = (sra hi, 31)
+  //  else:
+  //   lo = (srl hi, shamt[4:0])
+  //   hi = 0
+  SDValue Not = DAG.getNode(ISD::XOR, DL, MVT::i32, Shamt,
+                            DAG.getConstant(-1, MVT::i32));
+  SDValue ShiftLeft1Hi = DAG.getNode(ISD::SHL, DL, MVT::i32, Hi,
+                                     DAG.getConstant(1, MVT::i32));
+  SDValue ShiftLeftHi = DAG.getNode(ISD::SHL, DL, MVT::i32, ShiftLeft1Hi, Not);
+  SDValue ShiftRightLo = DAG.getNode(ISD::SRL, DL, MVT::i32, Lo, Shamt);
+  SDValue Or = DAG.getNode(ISD::OR, DL, MVT::i32, ShiftLeftHi, ShiftRightLo);
+  SDValue ShiftRightHi = DAG.getNode(IsSRA ? ISD::SRA : ISD::SRL, DL, MVT::i32,
+                                     Hi, Shamt);
+  SDValue Cond = DAG.getNode(ISD::AND, DL, MVT::i32, Shamt,
+                             DAG.getConstant(0x20, MVT::i32));
+  SDValue Shift31 = DAG.getNode(ISD::SRA, DL, MVT::i32, Hi,
+                                DAG.getConstant(31, MVT::i32));
+  Lo = DAG.getNode(ISD::SELECT, DL, MVT::i32, Cond, ShiftRightHi, Or);
+  Hi = DAG.getNode(ISD::SELECT, DL, MVT::i32, Cond,
+                   IsSRA ? Shift31 : DAG.getConstant(0, MVT::i32),
+                   ShiftRightHi);
+
+  SDValue Ops[2] = {Lo, Hi};
+  return DAG.getMergeValues(Ops, 2, DL);
+}
+
 //===----------------------------------------------------------------------===//
 //                      Calling Convention Implementation
 //===----------------------------------------------------------------------===//
diff --git a/lib/Target/Mips/MipsISelLowering.h b/lib/Target/Mips/MipsISelLowering.h
index f95e0dc..a38bb2f 100644
--- a/lib/Target/Mips/MipsISelLowering.h
+++ b/lib/Target/Mips/MipsISelLowering.h
@@ -135,6 +135,8 @@ namespace llvm {
     SDValue LowerFRAMEADDR(SDValue Op, SelectionDAG &DAG) const;
     SDValue LowerMEMBARRIER(SDValue Op, SelectionDAG& DAG) const;
     SDValue LowerATOMIC_FENCE(SDValue Op, SelectionDAG& DAG) const;
+    SDValue LowerShiftLeftParts(SDValue Op, SelectionDAG& DAG) const;
+    SDValue LowerShiftRightParts(SDValue Op, SelectionDAG& DAG, bool IsSRA) const;
 
     virtual SDValue
       LowerFormalArguments(SDValue Chain,
diff --git a/test/CodeGen/Mips/shift-parts.ll b/test/CodeGen/Mips/shift-parts.ll
new file mode 100644
index 0000000..38cbf28
--- /dev/null
+++ b/test/CodeGen/Mips/shift-parts.ll
@@ -0,0 +1,29 @@
+; RUN: llc -march=mipsel < %s | FileCheck %s
+
+define i64 @shl0(i64 %a, i32 %b) nounwind readnone {
+entry:
+; CHECK: shl0
+; CHECK-NOT: lw $25, %call16(__
+  %sh_prom = zext i32 %b to i64
+  %shl = shl i64 %a, %sh_prom
+  ret i64 %shl
+}
+
+define i64 @shr1(i64 %a, i32 %b) nounwind readnone {
+entry:
+; CHECK: shr1
+; CHECK-NOT: lw $25, %call16(__
+  %sh_prom = zext i32 %b to i64
+  %shr = lshr i64 %a, %sh_prom
+  ret i64 %shr
+}
+
+define i64 @sra2(i64 %a, i32 %b) nounwind readnone {
+entry:
+; CHECK: sra2
+; CHECK-NOT: lw $25, %call16(__
+  %sh_prom = zext i32 %b to i64
+  %shr = ashr i64 %a, %sh_prom
+  ret i64 %shr
+}
+